cryptsetup-fvault2Dump - Man Page

cryptsetup fvault2Dump [<options>] <device>

Dump the header information of a FVAULT2 (FileVault2 compatible) device.

If the --dump-volume-key option is used, the FVAULT2 device volume key is dumped instead of header information. You have to provide password or keyfile to dump volume key.

Beware that the volume key can be used to decrypt the data stored in the container without a passphrase. This means that if the volume key is compromised, the whole device has to be erased to prevent further access. Use this option carefully.

<options> can be [--dump-volume-key, --volume-key-file, --key-file, --keyfile-offset, --keyfile-size, --timeout].

--batch-mode,  -q

Suppresses all confirmation questions. Use with care!

If the --verify-passphrase option is not specified, this option also switches off the passphrase verification.

--debug or --debug-json

Run in debug mode with full diagnostic logs. Debug output lines are always prefixed by #.

If --debug-json is used, additional LUKS2 JSON data structures are printed.

--dump-volume-key,  --dump-master-key (OBSOLETE alias)

Print the volume key in the displayed information. Use with care, as the volume key can be used to bypass the passphrases, see also option --volume-key-file.

--help,  -?

Show help text and default parameters.

--key-file,  -d name

Read the passphrase from file.

If the name given is "-", then the passphrase will be read from stdin. In this case, reading will not stop at newline characters.

See section NOTES ON PASSPHRASE PROCESSING in cryptsetup(8) for more information.

--keyfile-offset value

Skip value bytes at the beginning of the key file.

--keyfile-size,  -l value

Read a maximum of value bytes from the key file. The default is to read the whole file up to the compiled-in maximum that can be queried with --help. Supplying more data than the compiled-in maximum aborts the operation.

This option is useful to cut trailing newlines, for example. If --keyfile-offset is also given, the size count starts after the offset.

--timeout,  -t <number of seconds>

The number of seconds to wait before timeout on passphrase input via terminal. It is relevant every time a passphrase is asked. It has no effect if used in conjunction with --key-file.

This option is useful when the system should not stall if the user does not input a passphrase, e.g. during boot. The default is a value of 0 seconds, which means to wait forever.

--usage

Show short option help.

--version,  -V

Show the program version.

--volume-key-file,  --master-key-file (OBSOLETE alias)

Use a volume key stored in a file. The volume key is stored in a file instead of being printed out to standard output.

Report bugs at cryptsetup mailing list or in Issues project section.

Please attach output of the failed command with --debug option added.

Cryptsetup FAQ

cryptsetup(8), integritysetup(8) and veritysetup(8)

Part of cryptsetup project.